aperture ring on lens

A

astraman1

Messages
328
Name
nick
Edit My Images
Yes
if i set the aperture ring to the lowest setting on my lens instead of the auto

why wont it let me take a photo ????

its a pentax k100d super

thanks in advance
 
Never used a pentax, but on Nikon you set the aperture on the lens to its highest number so f/16 or f/22 and then control the aperture in the camera.
 
i normally leave it on a and control it from the camera but i was messing about and as i zoomed in i could not get it to go lower than 5.9 even tho when zoomed out it will go to 4 so i set it to its lowest on the aperture ring to take it out of the camera function and it would not shoot if you get my explanation
 
astraman1 said:
i normally leave it on a and control it from the camera but i was messing about and as i zoomed in i could not get it to go lower than 5.9 even tho when zoomed out it will go to 4 so i set it to its lowest on the aperture ring to take it out of the camera function and it would not shoot if you get my explanation
Click to expand...

Most budget to mid range zoom lenses change the aperture as you zoom. The lens will say f/4-5.9 on it somewhere. This shows the minimum apertures of that lens. At its widest the aperture will be f/4, fully zoomed the aperture will be stopped down slightly.

This is why pro lenses cost more, as the minimum (or maximum if you look at it that way) aperture is fixed thorough the zoom range, usually at f/2.8 or f/4

Stick the aperture back to the highest number on the lens, and just control it through the camera.
 
i have done i just wondered why it wouldnt shoot thats all or why have the option on the lens if i cant use it lol ohh well thanks guys

the lens in question is my best one its a sigma 70-300
 
Last edited:
i struggle to blur out the background thats why i tryed it will have to invest in another lens i think with a lower f number
 
astraman1 said:
i have done i just wondered why it wouldnt shoot thats all or why have the option on the lens if i cant use it lol ohh well thanks guys

the lens in question is my best one its a sigma 70-300
Click to expand...

How close were you? Many cameras won't fire if the image is not in focus, so if you were closer than the minimum distance possible with that lens, it won't shoot.
 
astraman1 said:
i have done i just wondered why it wouldnt shoot thats all or why have the option on the lens if i cant use it lol ohh well thanks guys

the lens in question is my best one its a sigma 70-300
Click to expand...

Because its not communicating with the camera. If you do this on a Nikon is throws up a FEE error and locks the camera up until you set the aperture back to the highest.
 
was in focus its the one thing i like about this lens its easy to focus sometimes struggle with the kit lens as its very minute movements to get in focus

i like the look when people blur whats in the background but with not being able to go down that low on the f number its impossible
 
astraman1 said:
was in focus its the one thing i like about this lens its easy to focus sometimes struggle with the kit lens as its very minute movements to get in focus

i like the look when people blur whats in the background but with not being able to go down that low on the f number its impossible
Click to expand...

You should get reasonable blur at 300mm and the lowest aperture you can go. Make sure the subject is far away from the background though.
Sounds like you want a 50mm f/1.8 or similar.
 
astraman1 said:
was looking at a couple on ebay any recomendations for a decent one
Click to expand...

Not for Pentax no, not my field at all. I'm sure they must do a 50mm f/1.8. Or maybe a sigma 50mm f/1.8.
 
Sorry i can't help much as I too use Nikon but it may be worth speaking to another Pentax user. Drop Lynton on here a PM he's a Pentax user and will probably be able to point you in the correct direction as far as lenses are concerned.
 
You need to set the relevant custom function to allow the aperture ring to be used in a position other than 'A' - just change 'Using Aperture Ring' to the other option and you'll be able to use it fine.

Merry Christmas!
 
Last edited:
brilliant just found it thanks

merry christmas to you to mate much appreciated
 
Last edited:
Nick, as you probably know any Pentax K mount lens and many K mount lenses from third party manufacturers will fit current Pentax DSLRs. The only problem I have heard of is in the Pentax section on this link -

http://rick_oleson.tripod.com/index-99.html

Therefore there are lots of old K mount lenses around that will fit easily and work perfectly. I'm using a Sigma 70-210mm zoom and a Pentax 55mm f1.8, both about 30 years old on my Pentax DSLR.

If the aperture ring on an old lens has an "A" after the largest f number then the camera will control the aperture and any of the cameras exposure settings, eg Av, Tv etc will work, though you may, depending on the age of the lens, have to focus manually. If there is no "A" then the metering will have to be manual.

This is a good guide to using old K mount lenses -

http://www.robertsdonovan.com/?p=1181

Dave
 
Not neccessarily, if you hit the green button on a Pentax DSLR then it will provide a quick shutter speed to use even if it can't detect the aperture as pre K-A type lenses (original K mount) don't have the electronic contacts, it works on the actual light coming through the stopped down aperture.

On my dads K-X it works fine in Av mode with them, contacts or not, you just have to set the aperture on the lens and it works fine.
 
thanks for the replies again i will have a look throught the links i can now do what i want with my current lens but i think i will be getting into portaits so i will be looking for a new lens soon for that
 
You must log in or register to reply here.
Back
Top